AU
C054300

DTC C054300 indicates an abnormal electrical signal from Pressure Sensor 2 in the IPB (Intelligent Power Brake) electro-hydraulic module, specifically a short to power, short to ground, or open circuit in the signal circuit — Atto 3

Braking System

DTC C054300 indicates an abnormal electrical signal from Pressure Sensor 2 in the IPB (Intelligent Power Brake) electro-hydraulic module, specifically a short to power, short to ground, or open circuit in the signal circuit.

This sensor monitors brake master cylinder pressure (or wheel cylinder pressure channel 2) and provides a key input signal for ESC (Electronic Stability Control) and brake assist functions.

The ECU logs a hardware-level fault when it detects the sensor voltage signal falling outside the calibrated range (typically below 0.3V or above 4.7V, depending on the 5V reference voltage division logic).

This fault forces the IPB into a degraded mode, disabling ESC/ESP and Automatic Emergency Braking (AEB) functions.

The system may trigger limp mode (reducing brake assist).

In extreme cases, the brake pedal hardens or braking distance increases, posing a serious safety hazard.

4
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Pressure sensor internal open or short circuit: Damaged pressure-sensitive element or internal conditioning circuit causes an abnormal output signal.
  • 2Poor wiring harness connector contact: Backed-out pins, oxidation, or corrosion due to water ingress at the 32-pin (or 24-pin) connector on the IPB electro-hydraulic module, causing an intermittent or continuous open circuit.
  • 3Wiring harness wear and short circuit: Sensor wiring harness insulation ages in the high-temperature motor compartment and rubs against metal body edges, causing a short to ground or short to power.
  • 4IPB ECU internal sampling circuit fault: Damaged ECU analog-to-digital converter (ADC) channel or failed reference voltage regulator prevents correct reading of sensor signals.
  • 5Power supply or ground circuit fault: blown sensor 5V reference voltage circuit fuse or loose ground terminal, causing sensor power loss.
What To Do
  • 1
    Diagnostic tool check: Use the BYD VDS or Bosch KTS diagnostic tool to read the complete fault codes and freeze frame data. Check for an accompanying C054200 (Pressure Sensor 1 fault) or other IPB communication faults. Record the vehicle speed and brake pedal status at the time of the fault.
  • 2
    Visual and connector inspection: Disconnect the 12V battery negative terminal. Check the IPB electro-hydraulic module electrical connector (usually on the left side of the firewall or at the ABS pump location). Inspect the pins for oxidation or backing out, and check the wiring harness for wear or crush marks, especially the protective conduit near high-temperature areas in the engine compartment.
  • 3
    Static voltage measurement: Reconnect the battery. Turn the ignition switch to the ON position (do not depress the brake pedal). Use a multimeter to measure the voltage of the Pressure Sensor 2 signal wire (typically a specific connector pin, such as pin X). The normal reading is 2.0-2.5V (zero-pressure reference). A reading of 0V, 5V, or a floating voltage confirms a wiring fault.
  • 4
    Sensor power supply and ground check: Measure the voltage between the sensor power supply pin (5V Ref) and the ground pin to confirm the ECU provides a stable 5V reference voltage. Ground resistance must be less than 1Ω.
  • 5
    Harness continuity and insulation test: Disconnect the IPB and ECU connectors. Measure the signal harness continuity resistance (< 1 Ω) and insulation resistance to ground/power (> 10 MΩ). Inspect for short circuits.
  • 6
    Sensor replacement verification: If the wiring harness is normal, replace the IPB electro-hydraulic module assembly (the pressure sensor is usually unavailable separately; replace the entire assembly). After replacement, perform the brake system bleeding procedure, sensor zero-point calibration, and ESC function test.
Real-World Cases
BYD DTC AI Analysis

Song PLUS DM-i — Stiff Brake Pedal with Multiple System Warnings

✓
The instrument cluster displayed 'Braking System Fault' and 'Automatic Emergency Braking Function Limited'. Fault codes: C054300 and U012100 (IPB communication fault). Inspection found the IPB electro-hydraulic module at the firewall. The wiring harness retaining clip above it had detached, allowing the harness to rub against the engine heat shield edge. This wore through the insulation on pressure sensor 2's signal wire, shorting the copper core to ground. Repaired the damaged wiring (re-wrapped and fitted with corrugated sleeving), rerouted the harness to avoid contact, cleared the fault codes and performed IPB pressure sensor calibration. Fault resolved.
BYD DTC AI Analysis

BYD Han EV: ESC warning light stays on after driving through water

✓
After driving through flooded roads during heavy rain, the dashboard ESC warning light illuminated. VDS detected C054300 (current fault). Inspection of the IPB electro-hydraulic module connector revealed obvious water inside. Water ingress caused electrolytic corrosion between pins A12 (pressure sensor 2 signal) and A13 (ground), increasing contact resistance (measured 5.6Ω). Repair: Thoroughly cleaned the connector with electronic contact cleaner, blow-dried it, applied conductive grease, and replaced the waterproof seal ring. Fault did not reappear.
BYD DTC AI Analysis

Tang DM-i intermittent brake boost failure

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Customer reported intermittent hard brake pedal with the warning light flickering. Scan tool showed historic fault code C054300; freeze frame data indicated brake pressure sensor 2 signal voltage was 0.02V (short to ground) when the fault occurred. Wiggling the IPB wiring harness reproduced the fault. Found pin 8 (sensor power supply) on the electro-hydraulic module connector had recessed, causing poor contact with the sensor terminal. Under vibration, this intermittently disconnected and the ECU interpreted this as a short to ground. Repair: Replaced IPB connector assembly (or repaired pin), ensuring all terminal heights are uniform. Fault resolved.
BYD DTC AI Analysis

Replaced IPB assembly on Seal, fault persists

✓
After an accident, the IPB electro-hydraulic module was replaced, but DTC C054300 would not clear. The new module carried an aftermarket part number; though externally identical, its internal pressure sensor 2 calibration parameters did not match the vehicle. Further investigation showed the technician skipped the 'post-IPB replacement online configuration' procedure, so the ECU could not recognize the new sensor's characteristic curve. Solution: Performed the 'IPB replacement' online configuration using BYD VDS, wrote the correct parameter calibration values, performed brake line bleeding and pressure sensor zero-point learning. Fault resolved.
Other Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For the BYD Song MAX (2017–2019), DTC B1108 indicates a short circuit in the PM2.5 air quality detection module (dust sensor) or its wiring harness. The sensor uses laser scattering to detect in-cabin and outside PM2.5 concentrations and transmits data to the HVAC ECU via the LIN bus or an analog signal. Short circuit conditions include: 1) Sensor power supply wire (+5V/+12V) shorted to ground 2) Signal wire shorted to power or ground 3) Short circuit in the sensor's internal photoelectric detection circuit This fault prevents the automatic climate control from switching between fresh air and recirculation based on air quality. The system enters fail-safe mode (typically forced recirculation). Severe short-circuit current can destroy the HVAC ECU sampling circuit. The system classifies this as a Level 3 severe fault and restricts vehicle operation to prevent electrical fires or controller damage. For other BYD models (such as the Qin EV, E5, and Song DM), B1108 indicates a driver-side sunload sensor fault, reflecting differences in DTC definitions across models.B110811This DTC indicates a short circuit in the air conditioning system PM2.5 air quality sensor (rapid detector). Specifically, abnormal continuity exists between the sensor power supply circuit or signal output circuit and body ground or battery positive. This causes the control module (ACU/air conditioning controller) to detect abnormal current or a voltage signal outside the valid range (typically 0V or supply voltage). The PM2.5 sensor monitors internal and external particulate concentrations, providing the data the automatic air conditioning system uses to switch between fresh air and recirculation modes. A short circuit disables the air quality monitoring function. This fault may force the air conditioning system into recirculation protection mode and trigger related thermal management system faults, as the air conditioning system acts as a key actuator in vehicle thermal management. In severe cases, the short circuit current can damage the internal sampling circuit of the air conditioning controller or overheat the wiring harness.
Data confidence: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.